WO2007071162A1 - A welding head for electric resistance welding and its manufacturing method - Google Patents

Abstract

A welding head for electric resistance welding is provided for spot welding lead wires of enamel wires by one side welding in production of electronic devices with small coils. The welding head includes a tip end and two electrodes extending integrally in parallel with each other from the tip end. A through partition groove is formed between the electrodes. There are insulating fillers and fixation in the partition groove, thereby reducing or eliminating fractures possibly occurring at the tip end of welding head.

Description

 Electric resistance welding head and preparation method thereof

Technical field

 The invention relates to an electric resistance welding head and a preparation method thereof, which can be applied to the production of various electronic components with small coils in the electronics industry and the microelectronics industry, and realizes spot welding of the enameled wire lead wire joints by single-sided welding. Background technique

 The two electrodes of the existing electric resistance welding head are arranged in a separate manner, and the two electrodes are independent of each other. When floating, the weldment is placed between the two electrodes, and the welding force is applied; when the welding force reaches the set value, the power is turned on, and the current flows from the two electrodes through the weldment and generates heat resistance. Thereby welding of the weldment is achieved.

 For related prior art, please refer to the Chinese invention patent No. 01114808.X announced on February 25, 2004. The electric resistance welding head is insulated and fixed by two electrodes, and the tips of the two electrodes are in ohmic contact with each other. .

 However, the prior art electric resistance welding head has at least the following defects: Since the two electrodes of the electric resistance welding head are arranged separately, the electric current cannot pass through the insulating layer of the enameled wire, so the above electric resistance welding with two separate electrodes The head cannot be spliced to the enameled wire.

 In addition, once every spot is welded, an ohmic contact portion at the tip of the two electrodes produces an electric spark. During continuous soldering, the ohmic contact portion continuously generates an electric spark, which inevitably causes a change in the ohmic contact portion and a final disappearance of the ohmic contact. Therefore, the electric resistance welding head having such a structure is unstable and has a long service life. Summary of the invention

 The technical problem to be solved by the present invention is to provide an electric resistance welding head which can be used for spot welding of an enameled wire in the production of various electronic components.

For the electric resistance welding head of the present invention, the above technical problem is solved as follows: An electric resistance welding head is provided, which comprises a welding head tip and two opposite arrangements extending in the same direction from both sides of the tip end of the welding head The electrode has a through-separating groove between the two electrodes. The two electrodes of the electric resistance welding head of the invention adopt a joint arrangement. When current flows from the two electrodes to the tip of the welding head, the tip of the welding head generates high temperature to smear the insulating layer on the enameled wire; when the insulating layer is removed After that, the current flows to the metal to be welded and is welded, thereby achieving direct splicing of the enameled wire. In addition, since the tip of the welding tip does not have an electric spark during the welding process, the structure of the electric resistance welding head is stable and has a long service life.

 As an improvement of the electric resistance welding head of the present invention, the two electrodes of the electric resistance welding head are insulated and fixed by the insulation groove at the end far from the tip end of the welding head, so that the electric resistance welding head can be reduced at the tip end of the welding head. The breakage can also be made to make the tip of the soldering tip small enough to be used on small pads of electronic components.

 For the preparation method of the electric resistance welding head of the present invention, the above technical problem is solved as follows: A method for preparing an electric resistance welding head is provided, which comprises the following steps:

 (1) processing the electrode material into a predetermined columnar body;

 (2) A through-separating groove is formed along the longitudinal axis from an end surface of the column body to a distance from the end surface of the other end. The partitioning groove defines the columnar body as a tip of the welding head and two integrally extending from both sides of the tip end of the welding head. Parallel electrode; and

 (3) The tip of the horn is machined into the desired shape.

 Compared with the prior art, the method for preparing the electric resistance welding horn of the present invention can at least achieve the following technical effects: Since two columns, the tip of the horn connecting the two electrodes and the two electrodes can be used by one columnar body The partitioning grooves are processed at one time, so that the machining process can be simplified and the material can be saved.

 As an improvement of the preparation method of the electric resistance welding head of the present invention, the two electrodes of the electric resistance welding head are insulated and fixed by the insulation groove at the end far from the tip end of the welding head, so that the structure of the electric resistance welding head can be further improved. Stable, reducing the possible breakage of the resistance weld head at the tip of the weld head, and making the tip of the weld head smaller. DRAWINGS

The method for preparing the electric resistance welding head and the electric resistance welding head of the present invention will be described in detail below with reference to the embodiments described in the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view showing the structure of an electric resistance welding head according to the present invention, wherein both electrodes of the electric resistance welding head are semi-cylindrical, 1-1 is a main view, and 1-2 is a side view.

 Fig. 2 is a schematic view showing the structure of the electric resistance welding head of the present invention, wherein the two electrodes of the electric resistance welding head are all sheet-like bodies, 2-1 is a main view, and 2-2 is a side view.

 3 is a schematic view showing an insulation fixing manner of two electrodes of the electric resistance welding head shown in FIG. 1, wherein the two electrodes of the electric resistance welding head are filled and fixed by insulating adhesive insulation at a partition groove away from the end of the tip end of the welding head. .

 Figure 4 is a schematic view showing an insulating manner of the two electrodes of the electric resistance welding head shown in Figure 2, wherein the two electrodes of the electric resistance welding head are filled and fixed by insulating adhesive insulation at a partition away from the end of the tip end of the welding head. .

 Figure 5 is a schematic view showing another manner of insulating and fixing two electrodes of the electric resistance welding head shown in Figure 1, wherein the two electrodes pass through an insulating gasket filled in the partitioning groove and an insulating sleeve correspondingly disposed on the outer periphery of the two electrodes. Insulated and fixed.

 Figure 6 is a schematic view showing an insulating manner of two electrodes of the electric resistance welding head shown in Figure 2, wherein the two electrodes pass through an insulating spacer filled in the partitioning groove and an insulating sleeve correspondingly disposed on the outer periphery of the two electrodes. Insulated and fixed.

 Figure 7 is a schematic view showing another manner of insulating and fixing the two electrodes of the electric resistance welding head shown in Figure 1, wherein the two electrodes are respectively provided with a connecting groove which is electrically connected to the separating groove at the end far from the tip end of the welding head, The electrodes are fixed by insert insulation.

 Figure 8 is a schematic view showing another manner of insulating and fixing the two electrodes of the electric resistance welding head shown in Figure 2, wherein the two electrodes are respectively provided with a connecting groove which is electrically connected to the separating groove at the end far from the tip end of the welding head, The electrodes are fixed by insert insulation. detailed description

 Referring to FIG. 1 and FIG. 2, the electric resistance welding head of the present invention comprises a welding head tip 3 and a pair of parallel electrodes la and lb integrally extending from both sides of the tip end 3, and between the two electrodes la and lb. A through-separation slot 2.

In the electronics industry and the microelectronics industry, the production of electronic components usually requires the soldering of the enameled wire. On the pad of the contact point, in order to facilitate the operation of the tip of the horn (ie, the working end face of the horn) on the pad, the working end face of the resistance welding horn must be smaller than the pad. The area of the pad actually used is small, about 1 x ¹ mm ² , so the working end of the tip of the horn must be reduced accordingly. In addition, in order to ensure that a large amount of current flows through the electric resistance welding head to generate high temperature at the tip 3 of the welding head and complete the welding, the electric resistance welding head of the present invention must ensure that the longitudinal sectional area at the tip 3 of the welding head is smaller than the two electrodes la Or the cross-sectional area of the lb is small. The electric resistance welding head is generally made of a hard and brittle tungsten-molybdenum metal material, so that the two electrodes la and lb are easily fixed at the tip end 3 and the electrode la or lb if they are only fixed by the tip 3 of the welding head. The joint breaks.

 In order to prevent the electric resistance welding head from breaking at the tip 3 of the welding head, the two electrodes la and lb of the electric resistance welding head of the present invention are insulated and fixed by the insulation groove at the 3-terminal end away from the tip end of the welding head, and the specific insulation filling and fixing manner The details are as follows:

 Referring to Figures 3 and 4, the two electrodes la and lb of the electric resistance welding head can be insulated and fixed by bonding: directly filling the separation tank 2 with a paste-like adhesive 4 (such as an insulating adhesive) to be insulated The adhesive is cured to achieve the purpose of insulating and fixing the two electrodes la and lb. It is also possible to apply an insulating adhesive such as an insulating adhesive to the surface of the insulating spacer 4 and the two electrodes la and lb, and then fill the insulating spacer 4 coated with the insulating adhesive in the separation groove 2, The insulation of the two electrodes 1a and 1b is achieved by the filling of the insulating spacer 4 and the bonding of the insulating adhesive.

In the above insulation fixing method, the insulating adhesive used is preferably a heat curing adhesive such as chipbonder 3609 (model 3609 heat curing adhesive) manufactured by Loctite, which is a one-component ring. The oxyresin thermal curing adhesive has a red paste appearance, a specific gravity of 1.38, a viscosity of 380 Pa.s at 25 ° C, a heat curing temperature of 130-150 ° C for about 30 minutes, and an adhesive strength of about 50 N/mm. ² , The insulation resistance coefficient is 1.8χ1017Ω·cm. The dielectric constant is 3.8 x 100 KHz. Due to its high heat resistance (Tg=148°C) and excellent electrical characteristics, chipbonder3609 maintains good bond strength at 100°C after curing, which is sufficient for insulating spacer filling in the separation tank 2. And bonding fixed use requirements.

Referring to Figures 5 and 6, the two electrodes la and lb of the electric resistance welding head can also be insulated and fixed by an external fixing method: firstly, an insulating spacer 4 is placed in the separation groove 2 of the two electrodes la and lb, and then The two electrodes la and lb are sleeved with an insulating sleeve 5 corresponding to the outer periphery of the filling position of the insulating spacer 4, thereby facing two The electrodes 1a and 1b are insulated and fixed. Note: In this insulation fixing method, the insulating cymbal 4 and the insulating sleeve 5 are preferably capable of withstanding a temperature of about 100 °C.

 Referring to FIG. 7 and FIG. 8, the two electrodes la and lb of the electric resistance welding head can also be insulated and fixed by the inserting method: the two electrodes la and lb are respectively perpendicular to the separation groove 2 at the end of the tip end of the welding head. The through groove 6 is inserted, and then the partition 2 and the groove 6 are filled with an insulator. The insulator may be paste-like, and the two electrodes la and lb may be insulated and fixed after being hardened, or the formed insulating material may be directly embedded in the partitioning groove 2 and the fitting groove 6 to realize the two electrodes la Insulated with lb. It should be noted that in the insulation of the insert method, the insulating spacer and the insert insulating material also need to withstand a high temperature of about 100. Further, the shape of the fitting groove 6 may be an I-shape, a dumbbell shape or the like, and only one of the fitting grooves 6 may be opened, or a plurality of the fitting grooves 6 may be opened.

 The two electrodes la and lb of the electric resistance welding head of the present invention are insulated and fixed by a spacer spaced apart from the tip end of the tip of the horn to reduce or avoid breakage which may occur at the tip 3 of the horn. At this time, the tip 3 of the soldering tip can be made small, and it can be conveniently used on the small pads of the electronic component lead-out contacts.

 The electric resistance welding head of the present invention is made of a tungsten-molybdenum metal material having sufficient hardness and sufficient high temperature, such as molybdenum metal, tungsten metal, tungsten silver, tungsten copper, tungsten carbide, and the like.

 The two electrodes la and lb of the electric resistance welding head of the present invention may each be a semi-cylindrical body, and may be other semi-columnar bodies having a shape such as a square shape or an elliptical shape, or may be a sheet-like body.

 Referring to Figure 1, when the two electrodes la and lb are processed into a semi-cylindrical body, the electric resistance welding head can be conveniently clamped in the matching welding head holder. At this time, the outer diameters of the electrodes la and lb may be about 3 - 5 mm, the overall length of the welding head is about 25 - 40 mm, and the width of the separation groove 2 between the two electrodes la and lb is about 0.05 - 0.20 mm, welding The thickness d of the tip end 3 is about 0.2-1.0 mm, and the end face of the tip end 3 of the horn can be processed into a suitable square, wedge or circular arc shape or the like according to actual needs.

Referring to FIG. 2, when the two electrodes 1a and 1b are processed into a sheet-like body, the two electrodes 1a and 1b may be provided with a mounting portion away from the tip end of the tip of the soldering tip, and a card slot or a through hole 8 is formed in the mounting portion. The electrodes la and lb are screwed to the output of the welder and to the metal block. At this time, the overall shape of the sheet-like body is wide and narrow, and the wide portion is the mounting portion 7. The thickness of the sheet body is about l-3mm, and the length is about 15-25mm; the diameter of the two card slots or through holes is about Φ3-Φ5ιηιη, the center distance is about 8-12mm, and the separation between the two electrodes la and lb The width of the groove 2 is about 0.02 - 0.5 mm, and the thickness d of the tip 3 of the welding head is about 0.2-1.0 mm. The end face of the horn tip 3 can also be processed into a square, wedge or circular arc shape as needed.

As mentioned above, the current flowing through the tip 3 of the electric resistance welding head of the electric resistance welding head is large, sometimes up to 1000A, and the temperature generated is also high (up to more than 1 ⁵⁰⁰ °C). The insulation and heat dissipation between the two electrodes la and lb must be handled.

 The first is the insulation between the two electrodes la and lb: The electric resistance welding head of the present invention is mainly used for capturing the enameled wire on the lead-out contact, and the wire diameter of the enameled wire is generally less than 0.50 mm, so the welding power source often adopts a low voltage and a large current. The output resistor is turned off, and the output voltage is often below 5V. Therefore, the insulation between the two electrodes la and lb is not high. Since the air has good insulation and heat dissipation, no additional insulating spacers are required at the two electrodes la and lb near the tip 3 of the horn. As for the insulation by air, the width of the separation groove 2 can be calculated: The insulation withstand strength of the air is 3000V-4000V/mm, and the voltage is 5V, and the separation groove 2 is larger than l/600mm-l/800mm. In other words, Even if the width of the separation groove 2 is made small, the insulation requirement between the two electrodes la and lb can be satisfied.

 As for the high temperature heat dissipation, the high temperature is mainly generated in the electric resistance welding head; 1: the working end face is connected early, that is, the tip end 3 of the two electrodes la and lb is connected. In the electric resistance welding head of the present invention, the actual size of the horn tip 3 is small, so that it is good to increase the volume and heat dissipation area of the horn clip or the output electrode metal block of the two electrodes la and lb. Ground heat. If necessary, air cooling and water cooling can be used to ensure that the temperature of the metal of the welding head is within the allowable temperature range (generally not exceeding 100 °C), which can greatly reduce the high temperature resistance of the insulating gasket 4 and the like. Claim.

Hereinafter, the preparation method of the electric resistance welding head of the present invention will be described in detail with reference to FIG. 1 to FIG. 8. Firstly, a 3×30 mm molybdenum rod AB is taken; and then a through hole is formed along the longitudinal axis from the A end of the molybdenum rod AB to 0.6 mm from the B end. The separation groove 2 on both sides of the molybdenum rod, the separation groove 2 is about 0.20 mm wide and 29.5 mm long, so that the molybdenum rod AB is processed into two parallel electrodes la and lb which are connected only at the B end; The longitudinal axis is centered, and the working end surface of the B end is processed into a desired shape, such as a square shape, a wedge shape and a circular arc shape, and the end surface area of the B end is slightly smaller than lxlmm ² ; finally, the shape is adapted to the separation groove 2 The insulating cymbal 4, for example, a mica plate, is coated with a paste-like heat-curing adhesive on the surface of the insulating gasket 4 and the two electrodes, and is filled in the AG section of the upper portion of the separation groove 2, and then solidified. The insulation of the two electrodes la and lb is achieved.

In the above method, the insulating spacer 4 filled in the separation groove 2 may be filled only from the tip end of the welding head 3 A part of one end can also fill most of the separation groove 2.

 In the method of producing the electric resistance welding boring head of the present invention, the longitudinal sectional area at the tip end 3 of the horn is smaller than the cross-sectional area of the two electrodes la and lb.

 In the preparation method of the electric resistance welding head of the present invention, the electric resistance welding head is preferably made of a tungsten-molybdenum metal material having sufficient hardness and sufficient high temperature, such as molybdenum metal, tungsten metal, tungsten silver, tungsten copper, tungsten carbide material, etc. to make.

 It should be noted that: the method of insulating and fixing the two electrodes 1a and 1b may be directly filled with an insulating adhesive, such as an insulating adhesive, in the separation groove 2; or may be attached to the insulating spacer 4 and the two electrodes la and lb. The surface is coated with an insulating adhesive, and the insulating gasket 4 coated with the insulating adhesive is filled in the partitioning groove 2; the insulating spacer 4 having the shape of the groove 2 can be filled and separated in the dividing groove 2, Then, an insulating sleeve 5 is disposed on the outer circumference of the two electrodes 1a and 1b corresponding to the filling position of the insulating spacer 4; in addition, the connecting slots 6 may be respectively opened at the ends of the two electrodes la and lb away from the tip end of the soldering tip. Then, the two electrodes 1a and 1b are fixedly fixed by an insulator.

 The electric resistance welding head prepared according to the above method is mounted on a "direct welding enameled wire spot welding machine" disclosed in Patent No. ZL01114785.7, and is made of a 0.12 mm ordinary enameled wire and a 0.12 mm thick scale copper plate. The weldment is assembled into a floating joint. The three welding parameters set are: output pulse amplitude 1.30V, output pulse time 12ms, welding force 0.7kg, welding life more than 20,000 solder joints, and the welding effect is ideal.

 The present invention is not limited to the above embodiment, regardless of the change in the shape or structure of the electric resistance welding head, the working end face of the electric resistance welding head formed by the tip of the welding head and the insulating groove of the two electrodes are insulated. And other means of fixing are considered to fall within the scope of protection of the present invention.

Claims

Claim 1. An electric resistance welding head, characterized in that: the electric resistance welding head comprises a welding head tip and two electrodes integrally extending from two sides of the tip end of the welding head, and a through separation is provided between the two electrodes The groove, the two electrodes are insulated and fixed at the separation groove away from the end of the tip of the horn.  2. The electric resistance welding head according to claim 1, wherein: the separation groove is filled with an insulating adhesive that is adapted to the shape of the separation groove, and the two electrodes are filled and fixed by insulating adhesive insulation. .  3. The electric resistance welding head according to claim 1, wherein: said separation groove is filled with an insulating gasket adapted to the shape of the separation groove, and the surface of the insulating gasket and the two electrodes are coated. The adhesive, the two electrodes are insulated and fixed by an insulating gasket coated with an adhesive.  4. The electric resistance welding head according to claim 1, wherein: the separation groove is filled with an insulating spacer adapted to the shape of the separation groove, and the outer circumference of the two electrodes corresponds to the insulating gasket An insulating sleeve that can hold two electrodes.  5. The electric resistance welding head according to claim 1, wherein: the two electrodes are respectively provided with at least one splicing groove which is electrically connected to the separation groove at one end away from the tip end of the horn, and the two electrodes are through the splicing Insulated and fixed.  The electric resistance welding head according to any one of claims 1 to 5, wherein the welding head is made of a tungsten-molybdenum metal material having sufficient hardness and sufficient high temperature resistance.  The electric resistance welding head according to any one of claims 1 to 5, characterized in that: the longitudinal sectional area d at the tip end of the horn is the cross-sectional area of the two electrodes.  The electric resistance welding head according to any one of claims 1 to 5, wherein the two electrodes are both cylindrical cylinders.  The electric resistance welding head according to any one of claims 1 to 5, wherein the two electrodes are plate-like bodies. The electric resistance welding head according to claim 9, wherein: the two electrodes are respectively provided with a mounting portion at one end away from the tip end of the welding head, and a slot or a through hole is formed in the mounting portion, and each electrode passes through the screw The connection is mounted to the metal block of the welder output electrode. A method of preparing an electric resistance welding horn, comprising the steps of:  (1) processing the electrode material into a predetermined columnar body;  (2) A through-separating groove is formed along the longitudinal axis from an end surface of the column body to a distance from the end surface of the other end. The partitioning groove defines the columnar body as a tip of the welding head and two integrally extending from both sides of the tip end of the welding head. Parallel electrode; and  (3) The tip of the horn is machined into the desired shape.  The method of manufacturing an electric resistance welding horn according to claim 11, wherein the manufacturing method further comprises insulating filling and fixing the two electrodes at a separation groove away from one end of the tip end of the horn.  13. The method of manufacturing an electric resistance welding horn according to claim 11, wherein: the two electrodes are filled and fixed by an insulating adhesive filled in the separation groove.  The method of manufacturing an electric resistance welding horn according to claim 11, wherein: the two electrodes are insulated by an adhesive filled on a surface of the separation groove and bonded to the two electrodes. The gasket is insulated and fixed.  15. The method of manufacturing an electric resistance welding horn according to claim 11, wherein: the two electrodes pass through an insulating spacer filled in the separation groove and are sleeved on the outer periphery of the end of the two electrodes away from the tip end of the horn. The insulation sleeve is insulated and fixed.  The method of manufacturing an electric resistance welding horn according to claim 11, wherein: the two electrodes are respectively provided with at least one splicing groove which is electrically connected to the separation groove at one end away from the tip end of the horn, and two electrodes Insulated and fixed by the inserting method.  The method of manufacturing an electric resistance welding horn according to claim 11, wherein the end surface of the tip of the horn is square, wedge-shaped or arc-shaped.  The method of manufacturing an electric resistance welding horn according to any one of claims 11 to 17, wherein the longitudinal section of the tip of the horn is smaller than the cross-sectional area of the two electrodes.  The method of producing an electric resistance welding horn according to any one of claims 11 to 17, wherein the horn is made of a tungsten-molybdenum metal material having sufficient hardness and sufficient high temperature resistance.